The invention related to an arrangement for cleaning ducts and passages, such as air-conditioning ducts or chimneys.
The invention also relates to a receiver unit and a transverse workhead which are part of the arrangement.
According to the prior art, cleaning apparatuses and methods are used where a brush at the end of a long guide wire cable is inserted into the duct to be cleaned. The brush is moved inside the duct and for enhanced cleaning effect it is rotated or caused to make jerking movements. An alternative solution involves a technique based on intense compressed-air blasting where the cleaning end progresses inside the duct by means of compressed air. Even compressed-air turbine brushes are known. During cleaning, an intense underpressure is created in the duct system which during brushing enables the removal by suction of loose dirt from the system. The rotational or jerking movement of the brush is achieved either by an electric or pneumatic drive, whereby the electrically or pneumatically driven motor is connected to the brush and the drive force is transmitted to the motor along the guide wire cable by means of electric or pressure lines. Solutions are also known where a flexible shaft rotates inside the guide wire cable, whereby the motor generating the drive force is situated at the opposite end of the guide wire cable with regard to the brush. The loose dirt from the duct system is led to outdoor air either without filtration or after prefiltration or, alternatively, it is released into the indoor air after filtration.
The prior art is hampered by several drawbacks. Particularly in the case of large duct diameters, great output capacity, adjustable rotational velocity and great driving torque are required of the drive unit to rotate and move the large brush in the desired manner.
Particularly when extensive air conditioning systems are being cleaned, the cleaning efficiency required is so high that the motor size and thereby weight of electric motor drives become too extensive to allow sensible movement of the motor on the guide wire cable. As the space to be cleaned is in practice filled by a mixture of dust and air, sparking of the electric motor inside the space to be cleaned constitutes a severe risk of fire and explosion. In addition, the duct system, which usually is made of an electrically conductive material, is problematic in combination with electric drives, as the electric lines inside the guide wire cable may in the case of a damaged wire cable short circuit in the duct system being cleaned, whereby there is not only a risk of fire and explosion but also of electric shock.
Pneumatic drives arc also hampered by several drawbacks. In order to achieve the power required for large duct systems, pneumatic compressors of such external dimensions are required that they must usually be arranged outside the building being cleaned. Such large compressors are either driven by combustion motors or alternatively, they require three-phase current which is not available in all real properties. Pneumatic compressors and motors are relatively loud and the pneumatic hoses required by the system are awkwardly moved inside the buildings. In addition, in pneumatically driven systems lubricating oil from the motor is spread into the duct system to be cleaned along with the compressed air. The oil spread into the duct system gives rise to odour nuisance and accelerates refouling of the pipes because the oil acts as an effective adhesion surface for the dirt particles.
Solutions based on a mechanical flexible shaft for their part are extremely heavy at the power levels required, and furthermore, the guide wire cable will easily be too loose to be inserted into the duct by pushing. Hereby the resulting friction is also excessive for the motor and transmission.
The prior art is further hampered by the aftertreatment of the dirt removed from the duct system. If the outlet air is prefiltered, some larger solid particle may break the filter system used at present, because the intense underpressure exerts intense suction moving all sizes of dirt particles toward the filter at high speeds. If, then, no filtration is performed, substances which are detrimental to health may spread into the environment.
The prior art is limited to the cleaning of air-conditioning ducts only and offers no means for cleaning planar surfaces or for treating such surfaces without dust nuisance. If the surface to be treated contains health-endangering substances, use of the prior art equipment may cause health detriments unless the workers protect themselves in the required fashion.
The present invention aims at eliminating the drawbacks hampering the prior art and at achieving an entirely novel type of system and method for cleaning air-conditioning ducts and other duct systems and chimney systems. A further aim is to apply the invention to dustfree cleaning and working of planar surfaces.
The invention is based on hydraulically generating the drive force for rotating the cleaning brush along the guide wire cable. According to a preferred embodiment of the invention, the loose dirt is collected into a receiver unit and the air exiting the receiver unit may then be after-filtrated. Further according to an advantageous embodiment of the invention, a transverse workhead equipped with a bevel gear and a suction hood is used for treating essentially planar surfaces.